Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2221—Control of flow rate; Load sensing arrangements
  • E02F9/2239—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance
  • E02F9/2242—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance including an electronic controller
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2278—Hydraulic circuits
  • E02F9/2292—Systems with two or more pumps
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2278—Hydraulic circuits
  • E02F9/2296—Systems with a variable displacement pump

Definitions

• the present invention relates to a landscape technology related to a control device of a construction machine.
• a plurality of switches arranged on an operation panel are operated to select and instruct a control suitable for each type of work. It is configured to execute the designated control.
• the purpose of the present invention is to disclose the burden on the operating system and the erroneous control mode selection operation.
• a work selection means for selecting a desired work from a plurality of basic work types performed by a construction machine, and a work selected by the work selection means.
• Means for selecting and instructing various controls suitable for the selected task are provided, and the operator can select the desired task and adapt to the task automatically selected. So that the following control contents can be obtained.
• a control suitable for the selected task is uniquely specified based on the task type selection operation. As a result, the burden on the operator and erroneous selection of various controls are eliminated.
• FIG. 1 is a block diagram showing one embodiment of a control device according to the present invention
• FIG. 2 is a block diagram showing a configuration of an operation panel
• FIG. Figure 4 is a front view showing the panel layout of the operation panel.
• Fig. 4 is a cross-sectional view taken along the line A-A in Fig. 3.
• Fig. 5 is a view showing the soft mode processing.
• FIG. 6 is a flowchart showing the processing procedure of the CPU shown in FIG. 1, and FIG. 18 is a governor.
• Fig. 19 is an explanatory diagram of the pump separation function
• Fig. 20 is a characteristic diagram showing the operation of the TVC valve
• Fig. FIG. 4 is a characteristic diagram showing the effect of the present invention.
• Figure 1 is no. An embodiment of the control device according to the present invention applied to the shovel 40 will be described.
• the second It has an operation panel OP that shows the configuration as shown in the figure.
• the operation panel OP has a panel surface as shown in Fig. 3 and a sectional view taken along the line A-A of Fig. 3 in Fig. 4.
• a flexible sheet 1 made of a synthetic resin is stretched. Although this sheet 1 has a light-shielding property, switch position display marks 21 to 2, light-on display marks 3, and character marks attached to appropriate places are provided. The translucent property is given to the design mark.
• buttons 4 1 to 4 1 1 1 are provided, respectively.
• a light-emitting diode 5 is provided on the back side of the sheet 1 at each of the portions where the mark 3 is attached.
• a liquid crystal display 6 is provided above the panel.
• an illumination lamp 8 for irradiating each of the translucent marks from the rear side force of the sheet 1 and a liquid crystal display 6 are provided on the rear side.
• a lighting lamp for irradiating from the side 9 is installed.
• Each of the above push button switches 41 to 41 is of a type that is turned on only when pressed, and presses the portion of the mark 2 ⁇ to 2 to press the sheet 1. It is turned on by bending.
• the following Table 1 shows the operation items of these switches 41 to 411 and the contents instructed by the operation. ⁇ Table 1>
• the power modes “S”, “L” and “H” are This is a control mode instructing the output of the engine and indicating the output ratio of the hydraulic pump when the engine output is set to 100.
• the output ratio of the above pump is, for example,
• the soft mode does not instantaneously shut off the oil flowing through the hydraulic actuator of the work equipment when the work equipment operation lever is returned to the neutral position. This means that the control mode is gradually reduced as shown in Fig.5.
• Priority mode increases the oil supply to the power cylinder's boom cylinder, arm cylinder, and turning motor. This is the control mode that instructs whether or not to perform the operation.
• the slewing lock means that the upper revolving superstructure of the power level is locked, and the fan means the fan of the heater.
• Signals S 1 to S 11 shown in FIG. 2 are signals indicating the instruction contents A to H shown in Table 1 above, and these signals are output via the output circuit 12. It is.
• the signals S 8 , S 9 and S are the buzzer 15, fan 16, and ⁇ , respectively.
• the signal S is applied to the lighting lamps 8, 9 and the lights (headlights, working lights) 18.
• S is a symbol having a multi-bit structure, and indicates the content of the instruction in accordance with the combination of the logical levels of the bits.
• FIG. 6 shows the processing procedure of the CPU 11 shown in FIG.
• step 100 when the power is turned on, that is, when the key switch of the pas
• the initial setting process for setting the most standard operation mode is executed (step 100). That is, the contents of the work mode counter are set to 1 and the work mode is set to “digging”, and the contents of the power mode counter are set to 1.
• the process of setting the power mode to "S”, the process of setting the auto-decel flag to "ON” and setting the auto-decel mode to "ON”, Set the soft flag to “0FF” by setting the drive flag to “L”, and set the drive speed flag to “L” to set the drive speed mode.
• step 101 If it is determined in step 101 that the switch 41 is set to 0N, the operation mode processing shown in FIG. 7 is executed. After the procedure is completed, the procedure
• a process of adding 1 to the contents of the work mode countdown is executed (step 12 1). Then, it is determined whether or not the content of the work mode counter is 4, 1, and 2. , (Steps 122, 122 and 124), and if none of the contents of the counter is 4, 1, or 2, In this case, the process for setting the work mode to "fine operation” and the process for setting the power mode counter to 2 and setting the power mode "L” The auto-decel flag is set to "L” and the auto-decel mode is set to "0FF" (steps 125). 0
• step 1226 the process of setting the work mode to “heavy excavation” and the process of setting the power mode to 0 are performed. And then. There are two types of processing: one is to set the mode to "H”, and the other is to set the auto-decel flag to "H” and set the auto-decel mode to "0N”. Each of them is executed (steps 127).
• step 1 2 3 determines whether the content of the work mode counter is 1, the process of setting the work mode to “digging” and the power
• the process of setting the contents of the mode counter to 1 and setting the mode to “S”, and the process of setting the auto decel flag to “H” and auto deceleration is executed (steps 128).
• step 1 24 if it is determined in step 1 24 that the content of the work mode counter is 2, the process of setting the work mode to “correct” is performed.
• the process of setting the power mode counter to 1 and setting the power mode to “S”, and setting the auto decel flag to “L” and setting the Each of the processes for setting the deceleration mode to “0 FF” is executed (steps 12 and 9) o
• the power mode and the auto-decel mode are set to the contents suitable for the work type. These modes can be arbitrarily changed by turning on the switches 42 and 43. That is, when the ON operation of the switch 42 is determined in the step 102 shown in FIG. 6, as shown in FIG. 8, the CPU 11 is turned on. -The content of the mode counter is incremented by 1 (step 1330). If the content of the counter is 3, then whether it is 3 or not and It is determined whether or not it is 1 (steps 131, 132), and if the power of those determinations is N0, the power is -If the capacity of the mode counter is 2, the power mode "L" is indicated.
• step 13 1 If it is determined in step 13 1 that the power of the power mode counter is 3, it is determined that the power of the counter is 3. After that (Step 1334), the power mode “HJ is instructed, and in Step 1332, the content of the above counter is 1 If it is determined that there is, a password mode "S" is instructed. According to this procedure, the power mode is changed each time the power mode switch 42 is operated.
• the power modes “S”, “L” and “H” are the contents of the power mode counters 1 and 2 respectively. Corresponds to 0.
• step 1443 it is determined whether or not the auto-decel flag is "H". If it is determined that the value is not "H”, the auto-cell "0FF" is instructed (step 1442), and it is determined that the value is "H”. In this case, the default cell “0N” is indicated (step 1443).
• step 104 in FIG. 6 when the 0N operation of the soft mode switch 44 is determined in step 104 in FIG. 6, as shown in FIG.
• the steps 150 to 153 according to the steps 140 to 143 in FIG. 9 are executed, and every time the switch 44 is operated to 0N.
• the software mode is changed at the same time.
• the priority is given as shown in FIG.
• One more is added to the contents of the mode countdown (step 170), so that the power of the countdown is ⁇ 4, a force, no, 1 or not.
• Each of them is judged whether it is 2 or not (Steps 171, 1772, and 1733), and all of the judgment results are NO.
• the content of the priority mode countdown is 3, "turn" is instructed (step 1774) o If it is determined in step 171 that the content of the counter is 4 at the above-mentioned countdown, the content of the counter is set to 0, and then the content of the counter is set to 0.
• Step 175) and the priority mode “standard” is specified (step 176). Further, if it is determined in step 172 that the content of the counter is 1, the priority mode "Boom” is instructed (step 1777). ) If the content of the counter is judged to be 2 in step 17 3, the priority mode “arm” is instructed (step 17). 8).
• the priority modes “standard”, “boom”, “arm” and “turn” are the contents of the priority mode power counters 0, 1, and 2, respectively. And 3 are supported. By changing the contents of the counter by operating the switch 4 s, it is possible to indicate an arbitrary priority mode. .
• steps 109, 110 and 111 in FIG. 6 the fan switch 49 and the wiper switch 410 are used in steps 109, 111 and 111. Lighting / Light switch 4 11 0N operation is determined.
• the procedures 200 to 20 according to the procedures 130 to 1336 in Fig. 8 are performed. 6, 210-216 and 220-226 are executed respectively.
• the CP 1 11 has an effect of displaying the processing results of the initial setting processing 100 shown in FIG. 6 and the processing results shown in FIGS. 7 to 17.
• the character marker shown in FIG. 3 is transmitted via the display drive circuit 19 shown in FIG. Turn on the light-emitting diode 5 located at the position of the hoop (heavy excavation). This allows the operator to see that the "heavy drilling” mode is currently being commanded.
• the CPU 11 inputs the output signals of the sensors 20 ⁇ to 2 On for detecting the engine water temperature, the amount of twisting material, the engine oil pressure, and the like, and receives these signals. It also has a function of displaying the sensor detection result and the above detection result on the liquid crystal display 6 via the display drive circuit 19.
• Signals S i to S 7 output from the operation panel OP are added to the pump controller 30 shown in FIG.
• variable displacement hydraulic pumps 31 and 32 shown in the figure are each driven by an engine 33 to provide a diagonal drive.
• the discharge pressure oil of the pump 31 is supplied through the Lo control valve 36 for the arm, the left travel control valve (not shown), the swing control valve, and the Hi control valve for the boom.
• the arm cylinder 41, the left running motor (not shown), the turning motor, and the bomber cylinder 42 are supplied to the arm cylinder 41, respectively.
• the discharge pressure oil of the pump 32 is used for the Hi operating valve 37 for the arm, the right operating valve (not shown), the bucket operating valve, and the L0 operation for the boom. Via the valves, the arm cylinder 41, the right-hand motor (not shown), the bucket cylinder 43 and the boom cylinder 42, respectively. Supplied 0
• pilot port 3 of the arm L0 operation valve 36 is activated. Pilot pressure oil is supplied to 6a, and power and power are supplied to the Hi-operation valve 37 for the arm 37 through the normally open solenoid valve 39 to the pilot port 37a. Then, pilot pressurized oil is supplied.
• the arm 44 is operated on the rear side of the vehicle body.
• the lever 38 a of the PPC valve 38 moves in the direction of arrow F. If operated, the pilot pressure oil is supplied to the pilot port 36b of the L0 operating valve 36 for the arm and to the pilot port 37b of the Hi operating valve 37 for the arm. The pressurized oil supplied to the outlet port 37 b is discharged from the pumps 31 and 32, respectively, so that the pressure oil is discharged from the arm cylinder 41. Supplied to the cylinder room. As a result, the arm 44 is driven toward the front of the vehicle body. As is well known, at the time of dumping, the arm 44 is driven forward of the vehicle body.
• the above-described traveling operation valve, turning operation valve, and the like also use a separate PPC valve having the same function as the PPC valve 38.
• the solenoid valve 39 is closed by a signal output from the pump controller 30.
• the arm Hi operation valve 37 is turned off. Since the force between the pilot port 37a and the PPC valve 38 is closed, the lever 38 of the valve 38 is forced to operate when it is operated in the E direction. Only the pressurized oil discharged from-is supplied to the arm cylinder 41-through the L0 operating valve 36 for the arm.
• a and b shown in Fig. 19 indicate the positions of the levers 38a attached to the PPC valve 38 when the valve 39 is open and closed, respectively.
• the relationship between the stroke amount and the discharge flow rate Q (i / min) of the pumps 31 and 32 is shown.
• the oil discharged from the two pumps 31 and 32 is being supplied to the dam cylinder 41 in a turbulent manner. If one of the pumps 32 is separated and supplied to only one pump 31 of the discharge hydraulic power cylinder 41, the flow rate change The amount of change in the lever stroke is large.
• valve 39 has the function of separating one pump 32 from the hydraulic supply path for the arm 44 when operated in the E direction. have .
• the pilot pressure oil is also supplied to the TVC valve 51.
• the pilot pressure oil controlled by the TVC valve 51 is supplied to the sub-bore actuator 34 via the CO valve 52 and the NC valve 53, In addition, it is supplied through a C.0 valve 54 and an NC valve 55 to the suction valve 35.
• a hydraulic system including the above-mentioned valves 515 is known, for example, from Japanese Patent Application Laid-Open No. 61-81587.
• the TVC valve 51 is provided to keep the combined absorption horsepower of the pump 3132 constant. That is, the valve 51 receives the discharge pressure ⁇ P 2 of the pump 3 13 2 and receives the average pressure as shown by the characteristics A i A 2 and A 3 in FIG.
• the pressure ( ⁇ + ⁇ 2) ⁇ 2 and the product of the combined discharge flow Q of the pumps 31 and 32 are constant, that is, the product is set so that the combined absorption horsepower is approximately constant.
• the tilt angles of the swash plates 31a and 32a are controlled via bore actuators 34 and 35.
• a characteristic selection signal is added to the TVC valve 51 from the con- troller 30. According to this signal, any one of the characteristics A1, A2 and A3 described above is applied. Selected and set.
• the CO valves 52 and 54 input the discharge pressures of the pumps 31 and 32, respectively, and when these discharge pressures exceed a predetermined cutoff pressure, they are set. It has the effect of rapidly reducing the discharge pressure of valves 52 and 54 and returning ramps 31a and 32a to the minimum position.
• the CO valves 52 and 54 are cut off as shown in FIG.
• the discharge flow rate Q of the pump can be rapidly reduced along G.
• the CO valves 52 and 54 are connected to a pump 50 via a normally closed solenoid valve 56.
• the solenoid valve 56 When the solenoid valve 56 is not energized, the C0 valves 52 and 54 perform the cut-off operation described above.
• the solenoid valve 56 When the solenoid valve 56 is closed by the output signal of the con- troller 30, the pilot pressure acts on the C0 valves 52 and 54, causing the above cuts. Since the to-off function is lost, the discharge pressures Pi and P2 of the pumps 31 and 32 can be increased up to the relief pressure of the relief valve (not shown). .
• NC valve 53 is used for all controls connected to pump 31. When the valve is in a neutral state, it acts to reduce the output pressure of the valve 53.
• the decrease in the output pressure of the NC valve 53 reduces the tilt angle of the swash plate 31a. Therefore, the NC valve 53 has a function of preventing the energy loss by reducing the discharge flow rate of the pump 31 when each operating valve is in the neutral state.
• the NC valve 53 has a function of preventing the energy loss by reducing the discharge flow rate of the pump 31 when each operating valve is in the neutral state.
• the NC valve 55 also has the same effect on the pump 32.
• the engine 33 shown in FIG. 1 is provided with a fuel injection pump 61 and a governor 62.
• the fuel control lever 62 a of the governor 62 is driven by the motor 63, and the driving position of the lever 62 a is detected by the sensor 64. It is.
• the throttle amount setting device 65 is composed of a dial 65a, a potentiometer 65b rotated by the dial 65a, and a force. It is made up.
• the electric governor controller 60 outputs the first throttle signal output from the setting device 65 and the pump controller 30.
• the second throttle signal is compared with the second throttle signal, and the motor 63 is driven based on the smaller one of the signals.
• the governor 62 controls the output torque of the engine 33 according to a characteristic as exemplified in FIG.
• the regulation line 1 in the figure is the maximum target engine speed by the first throttle signal or the second slot signal. Is set when the target engine speed is specified, and as the target engine speed indicated by the first or second throttle signal decreases, the target engine speed decreases.
• the regulation line ⁇ 2, i3, ... is determined sequentially. That is, the governor 62 has the function of a so-called speed governor.
• the work mode signal S1 input to the pump controller 30 includes “heavy drilling”, “digging”, “straightening”, and “fine drilling”. Indicate the force of each operation mode in “Operation”. Now, if the "heavy excavation” mode is instructed, as shown in step 1227 in FIG. 7, the power output from the operation panel OP Ichimo one de signal to S 2 of the content is "H", or auto-de-Ce Norre signal S content force of 2 "0 N _ [in such ⁇
• the controller 30 sets the output horsepower of the engine 33 to the high horsepower PS— ⁇ based on the content of the page mode “ ⁇ ”. And a process of setting the number of revolutions of the engine 33 to the high number of revolutions ⁇ ⁇ ⁇ .
• the combined absorption torque of the pumps 31 and 32 shows a magnitude according to the characteristic A′H in FIG.
• the second throttle signal indicating the maximum target rotation speed NA is output to the output signal of the throttle amount setting device 65 by the ganona controller 60. Are compared.
• the output signal of this setter 65 is currently set to a value that indicates the maximum target engine speed NA ', and in this case, the A motor drive signal corresponding to the maximum target engine speed NA ′ is applied to the governor drive motor 63 from the mouthpiece 60.
• the fuel control controller operates the fuel control unit 62 a so that the highest speed regulation line A is set.
• the output torque of the engine 33 and the combined absorption torque of the pumps 31 and 32 and the force are matched at the point ⁇ PH (maximum horsepower point). It will be.
• the output horsepower of the engine 33 (PS-H (the horsepower at the maximum horsepower point) and the engine speed ⁇ Automatically set to NA.
• the pump controller 30 uses the lever neutral detection sensor 71 to set each PPC valve.
• the operating levers attached to the are set to the neutral position. Only when this is detected, that is, when the power level 4 ⁇ is detected to be inactive, the decel signal is output to the Gano 'signal.
• the Nacontroller 60 In addition to the Nacontroller 60.
• the controller 60 sets the target rotation speed of the engine 33 based on the decel signal before the second throttle signal. A process for changing the maximum target rotation speed NA 'to the value ND' shown in FIG. 21 (a) is executed.
• the pump controller 30 When the power mode is set to "H" in the heavy excavation mode as described above, the engine noise and twisting cost during non-working time are extremely high. growing .
• the above decel signal is Since the engine speed is greatly reduced during the non-working time, the noise and the cost during the non-working time can be reduced.
• the pump controller 30 also has the function of turning off the pump separation function (see Table 2 above).
• the arm cylinder 41 is driven by both the forces of the pumps 31 and 32 and the pressurized oil discharged from the pumps 31 and 32.
• a force suitable for heavy excavation can be applied to the arm 41.
• the controller 30 causes the cut-off operation by the CO valves 52 and 54 to be "ON" when the heavy excavation mode is instructed. That is, the bias signal is not output to the normally closed solenoid valve 56, and the cutoff operation described above is performed to the CO valves 52 and 53. .
• the power mode H suitable for the heavy excavation work is selected, and the engine H is selected.
• the horsepower is automatically set to PS-H and the rotation speed is set to NA.
• the pump separation function, cutoff function, and autodecel function are automatically set to “0FF”, “0N”, and “ON”, respectively. It is.
• step 128 of FIG. 7 the power mode “S” is selected by the operation panel 0P, and the power mode is selected. Decel “ON” is selected. Therefore, the control port 30 outputs a signal for obtaining the equal horsepower characteristic A2 shown in FIG. 20 to the TVC valve 51, and also outputs the signal to the target. A second throttle signal indicating the engine speed NB 'is applied to the controller 60.
• the controller 60 Since the number of revolutions NB 'is smaller than the number of revolutions NA' of the setting device 65, the controller 60 corresponds to the target engine revolution number NB '.
• the motor drive signal is applied to the motor 63 to thereby set the regulation line ⁇ D shown in FIG. 21 (b). .
• the synthetic absorption torque of the pumps 31 and 32 and the output torque of the engine 33 are matched at the point P s ′, and as a result,
• the engine 33 is operated at an output horsepower of PS-S (PS-H) and a rotation speed of NB.
• the operating state is suitable for normal excavation.
• the auto de-energization "OFF" force is set as shown in step 1229 in FIG. . Even if the lever neutral position detection sensor 71 detects the neutral state, the control signal is output to the governor controller even if the lever neutral position detection sensor 71 detects the neutral state. Do not output to 60.
• both the pump separation function and the cutoff function are set to “ON” as shown in the thick line frame in Table 2. That is, an energizing signal is applied to the normally open solenoid valve 39 from the pump contact port 30 and the valve 39 is closed.
• the lever 38 of the PPC valve 38 is operated in the E direction, that is, the PPC valve 38 is operated in a direction to extend the cylinder 41.
• the force of the pump 31 acts on the hydraulic cylinder force discharged from the arm cylinder 41. That is, when the arm cylinder 41 is expanded, one of the pumps 32 is connected to the cylinder. Da 41 is separated from the power.
• the pump 32 is connected to the bucket cylinder 43 via a valve for valve operation (not shown), If "0 N" processing is performed, when the lever 38a of the PPC valve 38 is operated in the E direction, the arm cylinder 41 is actuated by the pump 31. The pump cylinder is operated by the pump cylinder with the pump 32.
• the pump controller 30 On the platform where the fine operation mode is instructed on the operation panel 0 P, the power mode “L” as shown in step 1 25 of FIG. Set by 0P. Then, the pump controller 30 is shown in the column of "fine operation mode” in Table 2. Perform the following processing to obtain the power mode "L”. That is, the horsepower characteristics shown in Fig. 20 are added to the TVC valve 51.
• a signal for obtaining A a is given, and the pump absorption torque characteristic shown in FIG. 21 (e) is set.
• the engine 33 is operated at an output horsepower of PS-L2 ( ⁇ PS-S ⁇ PS-H) and a rotation speed of Nc, with the exception of pump separation and cut-off.
• PS-L2 ⁇ PS-S ⁇ PS-H
• Nc rotation speed
• the power mode type and the ON / OFF of the auto cell are manually set.
• the cut-off function can be arbitrarily released by operating the cut-off release push switch 70 shown in Fig. 1. I can .
• PS-LI > PS-L 2
• Table 2 is the horsepower at the matching point P in Fig. 21 (b).
• This characteristic A cannot be obtained with the TVC valve 51, but it can be obtained, for example, as follows.
• the pressures Pi and P2 of the pumps 31 and 32 are respectively detected by the pressure sensors, and the rotational speed N of the engine 33 is determined by the rotational speed sensor. If the characteristic A H ′ is detected by the sensor 72, the characteristic A H ′ is a monotonically increasing function with the engine speed N as a variable. P 2) / 2, N, and force to determine the swash plate tilt angles of the pumps 31, 32 to obtain the absorption torque according to the above characteristic AH '. And can be done.
• the characteristic AH ' can be obtained.
• the switch 70 is pressed. During this time, it is also possible to cause the controllers 30 and 60 to execute the following processing.
• the set pressure of the main relief vanoleb respectively connected to the pumps 31 and 32 is set to the normal set pressure, and more than 10 to 2 b. Change the set pressure to O kg Zcii. Incidentally, these set pressures are naturally set higher than the cutoff pressures of the CO valves 52 and 54.
• a relief valve of a variable set pressure is used, and the switching of the valve is performed, for example, by a solenoid valve (not shown) controlled by a controller 30. Therefore, it is necessary to change the pilot pressure acting on the relief valve. It is. Of course, it is also possible to use a relief valve that can change the set pressure by directly applying an electrical signal.
• control device for a construction machine As described above, in the control device for a construction machine according to the present invention, only the operation of selecting the type of work is performed, and various controls suitable for the selected work are uniquely specified. Therefore, it is suitable for use in a construction machine in which it is required to reliably perform control suitable for various operations.

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Citations (4)

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• 1988
  • 1988-07-29 JP JP63190076A patent/JP2670815B2/ja not_active Expired - Lifetime
• 1989
  • 1989-07-19 DE DE68915273T patent/DE68915273T2/de not_active Expired - Fee Related
  • 1989-07-19 US US07/474,782 patent/US5077973A/en not_active Expired - Fee Related
  • 1989-07-19 EP EP19890908509 patent/EP0404953B1/en not_active Expired - Lifetime
  • 1989-07-19 WO PCT/JP1989/000721 patent/WO1990001587A1/ja active IP Right Grant
• 1990
  • 1990-03-27 KR KR1019900700657A patent/KR0140077B1/ko not_active IP Right Cessation

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